Overview: The Next Generation Mass Storage Stack (September 2009)
Table Of Contents
- Abstract
- Background
- Features of the Next Generation Mass Storage Stack
- Impact
- Background
- Impact
- Background
- Impact
- Background
- Impact
- Impact
- Introduction to the Agile View
- Changes to I/O and Mass Storage Subsystems
- Changes to Other Subsystems
- Migrating to the Agile View
- Conclusion
- Glossary
- Appendix A: Summary of Changes
- Appendix B: Using ioscan
- Appendix C: Using scsimgr
- Appendix D: Interpreting Lunpath Hardware Paths
- For more information
iobind
Binds a specific driver to a hardware path. This new command accepts a hardware
path, a driver name, and an optional instance number to assign. The drivers
involved must support online rebinding; otherwise, the rebinding can be deferred to
next reboot.
The ioscan command with the existing –M and –H options also binds a driver
to a hardware path, but does not attempt to unbind any existing driver at the
specified hardware path.
ioscan -b
Explicitly defers a binding operation until the next reboot.
ioscan -B
Lists any pending deferred binding operations.
ioscan -r
Removes any pending deferred binding operations.
ioscan -P property
Displays a device property. Use the following values for the property argument:
• health (new in HP-UX 11i v3)
• is_inst_replaceable (new in the HP-UX 11i v3 March 2008 release)
• error_recovery (new in the HP-UX 11i v3 March 2008 release)
• bus_type
• cdio
• is_block
• is_char
• is_pseudo
• b_major
• c_major
• minor
• class
• driver
• hw_path
• id_bytes
• instance
• module_name
• sw_state
• hw_type
• description
All these values, except as noted, were displayed in previous releases by using the
–F option.
lssf -s
Displays stale DSFs—devices that have no associated hardware.
rmsf -x
Removes stale entries from the I/O configuration as well as their associated DSFs.
Performance
In the performance arena, the mass storage stack takes advantage of multiple hardware paths and multiple CPUs
to parallelize many operations:
• Native multi-pathing and load balancing provide better use of I/O channel bandwidth.
• More concurrent I/O operations provide a dramatic reduction of I/O scan times, both at boot time and in
response to ioscan. Tests show scans completing up to ten times faster.
• Increased maximum I/O request size from 1 MB to 2 MB.
• Improved performance tracking tools, including more statistical information at all levels of the I/O system
and enhancements to sar to display data about tapes, HBAs, and separate lunpaths.
Impact
The impact of multi-pathing and load balancing is described in Multi-Pathing and Load Balancing
.
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